Julgoldite-(Mg)

The place where the mineral was first found and described — by convention, the reference point for the species.

The hue of the mineral itself. Often unreliable for identification — many species occur in several colours depending on trace impurities or radiation damage.

One of seven geometric families that describe a mineral's atomic symmetry: isometric (cubic), tetragonal, hexagonal, trigonal, orthorhombic, monoclinic, triclinic. Two non-crystalline classes — amorphous and icosahedral — also appear.

The lengths of the unit-cell edges (a, b, c) in ångströms — the smallest repeating box of atoms that builds the crystal.

The angles (α, β, γ) between unit-cell edges, in degrees. Cubic crystals have 90°/90°/90°; triclinic crystals can take any combination.

Edge-length ratios of the unit cell, normalised so b = 1. Lets you compare related species without quoting absolute ångström values.

The number of formula units contained in a single unit cell.

Chemical elements that make up the mineral's ideal formula, listed by atomic symbol with their share of the total mass.

Minor or trace elements outside the ideal formula but commonly detected in natural specimens. Often the cause of colour variation.